Statistics (Sections 9.1 - 11.1)

23) The dean of a major university claims that the mean time for students to earn a Masterʹs
degree is less than 5.5 years. Write the null and alternative hypotheses.
23)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Classify the conclusion of the hypothesis test as a Type I error, a Type II error, or a correct decision.
24) A health insurer has determined that the ʺreasonable and customaryʺ fee for a certain medical
procedure is $1200. They suspect that the average fee charged by one particular clinic for this
procedure is higher than $1200. The insurer wants to perform a hypothesis test to determine
whether their suspicion is correct. The hypotheses are:
H : μ = $1200
0
H : μ > $1200
1
where μ is the mean amount charged by the clinic for this procedure.
Suppose that the results of the sampling lead to rejection of the null hypothesis. Classify that
conclusion as a Type I error, a Type II error, or a correct decision, if in fact the average fee charged
by the clinic is $1200 .
A) Type II error B) Correct decision C) Type I error
24)
25) In 2000, the average duration of long-distance telephone calls originating in one town was
9.4 minutes. Five years later, in 2005, a long-distance telephone company performs a hypothesis
test to determine whether the average duration of long-distance phone calls has changed from the
2000 mean of 9.4 minutes. The hypotheses are:
H : μ = 9.4 minutes
0
H : μ ≠ 9.4 minutes
1
where μ is the mean duration, in 2005, of long-distance telephone calls originating in the town.
Suppose that the results of the sampling lead to nonrejection of the null hypothesis. Classify that
conclusion as a Type I error, a Type II error, or a correct decision, if in fact the mean duration of
long-distance phone calls has changed from the 2000 mean of 9.4 minutes.
A) Correct decision B) Type II error C) Type I error
25)
26) The mean score for all NBA games during a particular season was less than 103 points per game. If
a hypothesis test is performed, how should you interpret a decision that fails to reject the null
hypothesis (H0: μ = 103 H1: μ < 103)
26)
A) There is sufficient evidence to reject the claim μ < 103.
B) There is not sufficient evidence to support the claim μ < 103.
C) There is sufficient evidence to support the claim μ< 103.
D) There is not sufficient evidence to reject the claim μ < 103.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
27) Find the critical value for a two-tailed test with α = 0.10. 27)
4